Commit fd668423 authored by Marcelo Tosatti's avatar Marcelo Tosatti Committed by Avi Kivity
Browse files

KVM: PIT: remove usage of count_load_time for channel 0 



We can infer elapsed time from hrtimer_expires_remaining.

Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent 5a05d545

arch/x86/kvm/i8254.c

+31 −6
Original line number Diff line number Diff line
@@ -98,6 +98,32 @@ static int pit_get_gate(struct kvm *kvm, int channel) 
	return kvm->arch.vpit->pit_state.channels[channel].gate;

}



static s64 __kpit_elapsed(struct kvm *kvm)

{

	s64 elapsed;

	ktime_t remaining;

	struct kvm_kpit_state *ps = &kvm->arch.vpit->pit_state;



	remaining = hrtimer_expires_remaining(&ps->pit_timer.timer);

	if (ktime_to_ns(remaining) < 0)

		remaining = ktime_set(0, 0);



	elapsed = ps->pit_timer.period;

	if (ktime_to_ns(remaining) <= ps->pit_timer.period)

		elapsed = ps->pit_timer.period - ktime_to_ns(remaining);



	return elapsed;

}



static s64 kpit_elapsed(struct kvm *kvm, struct kvm_kpit_channel_state *c,

			int channel)

{

	if (channel == 0)

		return __kpit_elapsed(kvm);



	return ktime_to_ns(ktime_sub(ktime_get(), c->count_load_time));

}



static int pit_get_count(struct kvm *kvm, int channel)

{

	struct kvm_kpit_channel_state *c =
@@ -107,7 +133,7 @@ static int pit_get_count(struct kvm *kvm, int channel) 


	WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));



	t = ktime_to_ns(ktime_sub(ktime_get(), c->count_load_time));

	t = kpit_elapsed(kvm, c, channel);

	d = muldiv64(t, KVM_PIT_FREQ, NSEC_PER_SEC);



	switch (c->mode) {
@@ -137,7 +163,7 @@ static int pit_get_out(struct kvm *kvm, int channel) 


	WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));



	t = ktime_to_ns(ktime_sub(ktime_get(), c->count_load_time));

	t = kpit_elapsed(kvm, c, channel);

	d = muldiv64(t, KVM_PIT_FREQ, NSEC_PER_SEC);



	switch (c->mode) {
@@ -208,8 +234,6 @@ static int __pit_timer_fn(struct kvm_kpit_state *ps) 
		wake_up_interruptible(&vcpu0->wq);



	hrtimer_add_expires_ns(&pt->timer, pt->period);

	if (pt->period)

		ps->channels[0].count_load_time = ktime_get();



	return (pt->period == 0 ? 0 : 1);

}
@@ -305,11 +329,12 @@ static void pit_load_count(struct kvm *kvm, int channel, u32 val) 
	if (val == 0)

		val = 0x10000;



	ps->channels[channel].count_load_time = ktime_get();

	ps->channels[channel].count = val;



	if (channel != 0)

	if (channel != 0) {

		ps->channels[channel].count_load_time = ktime_get();

		return;

	}



	/* Two types of timer

	 * mode 1 is one shot, mode 2 is period, otherwise del timer */